1. Field of the Invention
The present invention relates to plasma generators, and more particularly to devices having movable electrodes for igniting plasma plumes.
2. Discussion of the Related Art
In recent years, the progress on producing plasma by use of microwave energy has been increasing. Typically, a plasma producing system includes a device for generating microwave energy and a nozzle that receives the microwave energy to excite gas flowing through the nozzle into plasma. One of the difficulties in operating a conventional plasma producing system is making an ignition system that does not interfere with the microwave energy in the nozzle. For example, a conventional ignition system includes an electrode having a tip remaining in the nozzle after ignition. The tip heated by the microwave energy in the nozzle is eroded to suffer a shortening of its lifespan. Also, the mechanism for holding the electrode may cause the leakage of microwave energy from the nozzle. Thus, there is a need for an ignition system which ignites plasma plumes in the nozzle that reduces leaking and/or interfering with the microwave energy in the nozzle.